The “classical” PIV technique is only capable of recording the projection of velocity into the plane of the laser sheet, i.e the out-of-plane velocity component is lost while the in-plane components are affected by an unrecoverable error due to the perspective transformation. For highly three-dimensional flow fields like lobed jet mixing flow, this may lead to substantial measurement error of the local velocity vector. In order to get the velocity three-components simultaneously to reveal the interaction and evolution of various vortices in the lobed jet mixing flow, a high-resolution stereoscopic PIV system is used in the present study to measure the near flow field of a lobed jet mixing flow. Based on the analyzing of the three-components and three-dimensional velocity fields of the stereoscopic PIV measurement results, the mixing characteristics in the lobed jet mixing flow is studied and the mechanism of the mixing enhancement in lobed jet mixing flow is discussed.